Herbicidal 4-trifluoromethyl-4-nitrodiphenyl ethers

ABSTRACT

Compounds of the formula   WHEREIN X is a hydrogen atom, a halogen atom, a trihalomethyl group, an alkyl group, or a cyano group, and Y is a hydrogen atom, a halogen atom, or a trihalomethyl group, AND COMPOSITIONS CONTAINING THESE COMPOUNDS EXHIBIT HERBICIDAL ACITIVITY.

United States Patent [191 Bayer et al.

[ June 10, 1975 HERBICIDAL 4-TRlFLUOROMETHYL-4- NITRODIPHENYL ETHERS [75] Inventors: Horst 0. Bayer, Levittown; Colin Swithenbank, Perkasie; Roy Y. Yih, Doylestown, all of Pa.

[73] Assignee: Rohm and Haas Company,

Philadelphia, Pa.

[22] Filed: Mar. 14, 1972 [21] Appl. No.: 234,656

[56] References Cited UNITED STATES PATENTS l/l969 Martin et al. 260/612 R 7/l969 Kato et al. 260/612 R X Primary ExaminerBernard Helfin Attorney, Agent, or FirmWilliam E. Lambert, III

[5 7 ABSTRACT Compounds of the formula 4 NO 2 wherein X is a hydrogen atom, a halogen atom, a trihalomethyl group, an alkyl group, or a cyano group, and

Y is a hydrogen atom, a halogen atom, or a trihalomethyl group,

and compositions containing these compounds exhibit herbicidal acitivity.

5 Claims, No Drawings H E R B IC [D AL 4-TRIFLUOROMETHYL-4-NITRODIPHENYL ETHERS trol agents. In a preferred embodiment of the invention, X is a halogen atom or a cyano group, and Y is a hydrogen atom or a halogen atom.

Examples of the compounds of the invention em- This invention relates to novel compounds which 5 braced y Formula I include? show activity as herbicides, to novel herbicidal compositions which contain these compounds. and to new methods of controlling weeds with these herbicidal compositions.

Certain diphenyl ethers have been shown to be effective weed control agents. However. the herbicidal effectiveness of a given diphenyl ether cannot be predicted from an examination of the substituent groups attached to the phenyl rings in the ether, and often quite closely related compounds will have quite different weed control abilities. Various diphenyl ethers may have overlapping or complementary areas of activity or selectivity, and can thus be useful in combination to control a variety of weeds upon application of a single composition. Furthermore, the diphenyl ethers heretofore disclosed as herbicides are not completely effective. An ideal herbicide should give selective weed control, over the full growing season, with a single administration at low rates of application. It should be able to control all common weeds by killing them as the seed,

' the germinating seed, the seedling, and the growing plant. At the same time, the herbicide should not be phytotoxic to the crops to which it is applied and should decompose or otherwise be dissipated so as not to poison the soil permanently. The known diphenyl ether herbicides fall short of these ideals, and it would thus be desirable to have new herbicides which show even more selective control of undesirable plants among desirable crop plants or which complement the known diphenyl ethers in activity.

In accordance with the present invention, there is provided a new class of novel diphenyl ethers having the formula wherein X is a hydrogen atom, a halogen atom, preferably a fluorine atom or a chlorine atom, a trihalomethyl group, preferably a trifluoromethyl group, a (C -C alkyl group, preferably a methyl group, or a cyano group, and Y is a hydrogen atom, a halogen atom, preferably a fluorine atom or a chlorine atom, or a trihalomethyl group, preferably a trifluoromethyl group. The alkyl protion of the alkyl-containing X substituents can have either a straightor branched-chain or a cyclic spatial configuration. These novel compounds have been found to show unexpected activity as weed con- 01,6!,a-trifluoro-p-tolyl-4-nitrophenyl ether.

2, a,a.a-tetrafluoro-p-tolyl-4-nitrophenyl ether,

Z-bromo-a.a,atrifluoro-p-tolyl-4-nitrophenyl ether.

2-chloro-a,oz,oz-trifluoro-p-tolyl-4-nitrophenyl ether,

01,01a-trifluoro-2-iodo-p-tolyl-4-nitrophenyl ether, 2,6-dichloro-a.01,a-trifluoro-p-tolyl-4-nitrophenyl ether.

Z-chloro-o a,a,01-tetrafluoro-p-tolyl-4-nitrophenyl ether, 2-cyano-a,0.a-trifluoro-p-tolyl-4-nitrophenyl ether,

Z-cyano-b,a,a,oztetrafluoro-p-tolyl-4-nitrophenyl ether.

2-cyano-6-chloro-ma,a-trifluoro-ptolyl-4- nitrophenyl ether, a,a,a,oz',a,a-hexafluoro-2,4-xylyl-4-nitrophenyl nitrophenyl ether, a ,0z ,a-trifluoro-2,4-xylyl-4-nitrophenyl ether,

Z-butyl-a,0:,a-trifluoro-p-tolyl-4-nitrophenyl ether,

2-chloro-6-ethyl-a,oz,a-trifluoro-p-tolyl-4- nitrophenyl ether, and the like.

The novel diphenyl ethers of the invention are useful both as preemergence and as postemergence herbicides. Preemergence herbicides are ordinarily used to treat the soil in which the desired crop is to be planted by application either before seeding, during seeding, or, as in most applications, after seeding and before the crop emerges. Postemergenee herbicides are those which are applied after the plants have emerged and during their growth period.

Among the crops on which the diphenyl ethers of the invention can be advantageously employed are, for example, cotton, soybeans, peanuts, beans, peas, carrots, corn, and other cereal crops.

The diphenyl ethers of the invention are useful for controlling weeds in rice crops. When used in transplanted rice crops, the ethers can be applied either preemergence or postemergence to the weeds that is, they can be applied to the'transplanted rice plants and their growth medium either before the weed plants have emerged or while they are in their early stages of growth. The ethers can be applied to the growth me dium either before or after the rice has been transplanted to that medium.

The diphenyl ethers of the invention can be applied in any amount which will give the required control of weeds. A preferred rate of application of the herbicides of the invention is from about 0.1 to about 12 pounds of the diphenyl ether per acre.

Under some conditions, the diphenyl ethers of the invention may be advantageously incorporated into the soil or other growth medium prior to planting a crop. This incorporation can be carried out by any convenient means, including by simple mixing with the soil, by applying the diphenyl ether to the surface of the soil and then disking or dragging into the soil to the desired depth, or by employing a liquid carrier to accomplish the necessary penetration and impregnation.

A diphenyl ether of the invention can be applied to the growth medium or to plants to be treated either by itself or, as is generally done, as a component in a herbicidal composition or formulation which also comprises an agronomically acceptable carrier. By agronomically acceptable carrier is meant any substance which can be used to dissolve, disperse, or diffuse a herbicidal compound in the composition without impairing the effectiveness of the herbicidal compound and which by itself has no detrimental effect on the soil, equipment, crops, or agronomic environment. Mixtures of the diphenyl ethers of the invention may also be used in any of these herbicidal formulations. The herbicidal compositions of the invention can be either solid or liquid formultions or solutions. For example, the diphenyl ethers can be formulated as Wettable powders, emulsifiable concentrates. dusts, granular formulations, aerosols, or flowable emulsion concentrates. In such formulations, the compounds are extended with a liquid or solid carrier and, when desired, suitable surfactants are incorporated.

It is usually desirable, particularly in postemergence applications, to include adjuvants, such as wetting agents, spreading agents, dispersing agents. stickers, adhesives, and the like, in accordance with agricultural practices. Examples of adjuvants which are commonly used in the art can be found in the John W. McCutcheon, Inc. publication Detergents and Emulsifiers 1969 Annual."

The diphenyl ether compounds of this invention can be dissolved in any appropriate solvent. Examples of solvents which are useful in the practice of this invention include alcohols, ketones, aromatic hydrocarbons, dimethylformamide, dioxiane, dimethyl sulfoxide, and the like. Mixtures of these solvents can also be used. The concentration of the solution can vary from about 2% to about 98% with a preferred range being about 25% to about 75%.

For the preparation of emulsifiable concentrates, the diphenyl ether can be dissolved in organic solvent such as benzene, toluene, xylene, methylated naphthalene, corn oil, pine oil, o-dichlorobenzene, isophorone, cyclohexanone, methyl oleate, and the like, or in mixtures of these solvents, together with an emulsifying agent which permits dispersion in water. Suitable emulsifiers include, for example, the ethylene oxide derivatives of alkylphenols or long-chain alcohols, mercaptans, carboxylic acids, and reactive amines and partially esterified polyhydric alcohols. Solvent-soluble sulfates or sulfonates, such as the alkaline earth salts or amine salts of alkylbenzenesulfonates and the fatty alcohol sodium sulfates, having surface-active properties can be used as emulsifiers either alone or in conjunction with an ethylene oxide reaction product. Flowable emulsion concentrates are formulated similarly to the emulsifiable concentrates and include, in addition to the above components, water and a stabilizing agent such as a water-soluble cellulose derivative or a water-soluble salt of a polyacrylic acid. The concentration of the active ingredient in emulsifiable concentrates is usually about to 60% and in flowable emulsion concentrates, this can be as high as about 75%.

Wettable powders suitable for spraying, can be prepared by admixing the compound with a finely divided solid, such as clays, inorganic silicates and carbonates, and silicas and incorporating wetting agents, sticking agents, and/or dispersing agents in such mixtures. The concentration of active ingredients in such formulations is usually in the range of about to 98%, preferably about 40 to 75%. A dispersing agent can constitute about 0.5% to about 3% of the composition, and a wetting agent can constitute from about 0.1% to about 5% of the composition.

Dusts can be prepared by mixing the compounds of the invention with finely divided inert solids which may be organic or inorganic in nature. Materials useful for this purpose include, for example, botanical flours, silicas, silicates, carbonates and clays. One convenient method of preparing a dust is to dilut: a Wettable powder with a finely divided carrier. Dust concentrates containing about 20 to of the active ingredient are commonly made and are subsequently diluted to about 1 to 10% use concentration.

Granular formulations formultions can be prepared by impregnating a solid as granular fullers earth, vermiculite, ground corn cobs, seed hulls, including bran or other grain-hulls, or similar material. A solution of one or more of the diphenyl ethers in a volatile organic solvent can be sprayed or mixed with the granular solid and the solvent then removed by evaporation. The granular material can have any suitable size, with a preferable size range of 16 to 60 mesh. The diphenyl ether will usually comprise about 2 to 15% of the granular formulation.

The diphenyl ethers of the invention can also be mixed with fertilizers or fertilizing materials before their application. In one type of solid fertilizing composition in which the diphenyl ethers can be used, particles of a fertilizer or fertilizing ingredients, such as ammonium sulfate, ammonium nitrate, or ammonium phosphate, can be coated with one or more of the ethers. The solid diphenyl ethers and solid fertilizing material can also be admixed in mixing or blending equipment, or they can be incorporated with fertilizers in granular formulations. Any relative proportion of diphenyl ether and fertilizer can be used which is suitable for the crops and weeds to be treated. The diphenyl ether will commonly be from about 5% to about 25% of the fertilizing composition. These compositions provide fertilizing materials which promote the rapid growth of desired plants, and at the same time control the growth of undesired plants.

The diphenyl ethers of the invention can be applied as herbicidal sprays by methods commonly employed, such as conventional high-gallonage hydraulic sprays, low-gallonage sprays, airblast spray, aerial sprays and dusts. For low volume applications a solution of the compound is usually used. The dilution and rate of application will usually depend upon such factors as the type of equipment employed, the method of application, the area to be treated and the type and stage of development of the weeds.

For some applications, it may be desirable to add one or more other herbicides along with diphenyl ethers of the invention. Examples of other herbicides which can be incorporated to provide additional advantages and effectiveness include:

CARBOXYLIC ACIDS AND DERIVATIVES 2,3,6-trichlorobenzoic acid and its salts 2,3,5,6-tetrachlorobenzoic acid and its salts 2-methoxy-3,5,6-trichlorobenzoic acid and its salts 2-methoxy-3,6-dichlorobenzoic acid and its salts 2-methyl-3,o-dichlorobenzoic acid and its salts 2,3-dichloro-o-methylbenzoic acid and its salts 2,4-dichlorophenoxyacetic acid and its salts and esters 2,4,5-trichlorophenoxyacetic acid and its salts and esters 2-methyl-4-chlorophenoxyacetic acid and its salts and esters 2-(2.4.5-trichlorophenoxy )propionic acid and its salts and esters 4-( 2,4-dichlorophenoxy )butyric acid and its salts and esters 4-(2-methyl-4-chlorophcnoxy)butyric acid and its salts and esters 2,3,-trichlorophenylacetic acid and its salts 3,6-endoxohexahydrophthalic acid dimethyl 2,3,5,-tetrachloroterephthalate trichloroacetic acid and its salts 2,2-dichloropropionic acid and its salts 2,3-dichloroisobutyric acid and its salts CARBAMIC ACID DERIVATIVES ethyl N,N-di(n-propyl)thiolcarbamate propyl N,N-di (n-propyl)thiolcarbamate ethyl N-ethyl-N-(n-butyl)thiolcarbamate propyl N-ethyl-N-(n-butyl)thiolcarbamate 2-chloroallyl N,N-diethyldithiocarbamate N-methyldithiocarbamic acid salts ethyl l-hexamethyleneiminecarbothiolate isopropyl N-phenylcarbamate isopropyl N-(m-chlorophenyl)carbamate 4-chloro-2-butynyl N(m-chlorophenyl )carbamate methyl N-(3,4-dichlorophenyl)carbamate PI-IENOLS dinitro-o-(sec-butyl)phenol and its salts pentachlorophenol and its salts SUBSTITUTED UREAS 3-( 3,4-dichlorophenyl)-l l -dimethylurea 3-phenyll 1 -dimethylurea 3-( 3,4-dichlorophenyl-3-methoxy-l l -dimethylurea 3-(4-chlorophenyl)-3-methoxyl l -dimethylurea 3-( 3,4-dichlorophenyl l -n-butyl- 1 -methylurea 3-( 3,4-dichlorophenyl l -methoxyl -methylurea 3-(4-chlorophenyl l -methoxyl -methylurea 3-(3,4-dichlorophenyl)-1,l,3-trimethylurea 3-( 3,4-dichlorophenyl l l -diethylurea dichloral urea SUBSTITUTED TRIAZINES 2-chloro-4,6-bis(ethylamino )-s-triazine 2-chloro-4-ethylamino-o-isopropylamino-s-triazine 2-chloro-4,6-bis( methoxypropylamino )-s-triazine 2-methoxy-4,6-bis( isopropylamino )-s-triazine 2-chloro-4-ethylamino-6-( 3-methoxypropylamino s-triazine 1 2-methylmercapto-4,6-bis(isopropylamino)-striazine i v 2-methylmercapto-4,6-bis(ethylamino)-s-triazine 2-methylmercapto-4-ethylamino-o-isopropylaminos-triazine 2-chloro-4,6-bis( isoropylamino )-s-triazine 2-methoxy-4,6-bis( ethylaminol-s-triazine 2-methoxy-4-ethylamino-6 isopropylamino-s-triazine 2-methylmercapto-4-( 2-methoxyethylamino)-6-isopropylamino-s-triazine DIPHENYL Enter: DERIVATIVES 2,4-dichloro-4'-nitrodiphenyl ether 2,4,6-trichloro-4'-nitrodiphenyl ether 2,4-dichloro-6-fluoro-4'-nitrodiphenyl ether 3-methyl-4'-nitrodiphenyl ether 3,5-dimethyl-4'-nitrodiphenyl ether I 2,4 '-dinitro-4-trifluoromethyldiphenyl ether Ill 2,4-dichloro-3'-methoxy-4'-nitrodiphenyl ether ANlLlDES N-( 3 ,4-dichlorophenyl )p opionamide N-( 3 ,4-dichlorophenyl )methacrylamide N-( 3-chloro-4-mcthylphenyl )-2-methylpentzmamide N-( 3-dichlorophcnyl )trimethylacetamide N-( 3,4-dichlorophenyl )-a,a-dimethylvaleramide N-isopropyl-N-phcnylchloroacetamide N-nbutoxymethyl-N-( 2,6-diethylphenyl chloroacetamide N-n-methoxymethyl-N-( 2,6-diethylphenyl chloroacetamide URACILS 5-bromo-3-s-butyl-6-methyluracil 5-bromo-3-cyclohexyl-1,6-dimethyluracil 3-cyclohexyl-5 ,fi-trimethyleneuracil 5-brom0-3-isopropyl-6-methyluracil 3-tert-butyl-5-chloro-6-methyluracil NITRTLES 2,6-dichlorobenzonitrile diphenylacetonitrile 3,5-dibromo-4-hydroxybenzonitrile 3 ,5-diiod0-4-hydroxybenzonitrile OTHER ORGANIC I-IERBICIDES 2-chloro-N,N-diallylacetamide N-( 1 ,1-dimethyl-2-propynyl)-3,5-dichlorobenzamide maleic hydrazide 3-aminol ,2,4-triazole monosodium methanearsonate disodium methanearsonate N,N,-dimethyl-ct,oz-diphenylacetamide N,N-di(n-propyl)-2,6-dinitro-4- trifluoromethylaniline N,N-di( n-p'ropyl )-2,6-dinitro-4-methylaniline N,N-di(n-propyl)-2,6-dinitro-4- methylsulfonylaniline O-(2,4 dichlorophenyl)-O-methyl-isopropylphosphoramidothioate 4-amino-3,5.o-trichloropicolinic acid 2,3-dichloro-l ,4-naphthoquinone di(methoxythiocarbonyl)disulfide 3-isopropyll "2,1 ,3-benzothiadiazine-(4)3"""2,2-

dioxide 6,7-dihydrodipyridol l ,2-a:2',1 '-c]pyrazidinium salts 1,1 -dimethyl-4,4'-bipyridinium salts 3,4,5 ,6-tetrahydro-3,5-dimethyl-2-thio-2'"l ,3,5-

thiadiazine.

When mixtures of herbicides are employed, the relative proportions which are used will depend upon the crop to be treated and the degree of selectivity in weed control which is desired.

The diphenyl ethers of the invention or their precursors can be prepared by reacting a suitably substituted phenol, or the potassium or sodium salt of the phenol, with a suitably substituted halobenzene, such as a chloroor fluorobenzene, in the presence of an alkaline agent.

The following examples will further illustrate this invention but are not intended to limit it in any way. In Table I, typical diphenyl ethers of the invention are listed with their melting points and elemental analyses. Specific, illustrative preparations of the compounds of Examples 1 to 3 are described after Table I.

(31" tracted with benzene. The extract is dried, filtered I through activated silica gel (10 g.) and the solvent removed. The residue is taken up in isopropanol/hexane LC l 1:3) cooled to 20C, decanted from an oily precipitate', and the solvents stripped off. The residue (2.9 g.) Y 1 X. is distilled to give 2-chloro-a,a,a-trifluoro-p-tolyl-4- nitrophenyl ether (1.6 g. 31%) b.p. 2385C/ 0.3 mm which when induced to crystallize has a melting range l of 6268C. An'impurity isolated from a preparation following this procedure has been identified as 4- carbomethoxy-Z-chlorophenyl-4-nitrophenyl ether. Ila. 2-Chloro-a,a.0z-trifluoro-p-tolyl phenyl ether 1 Potassium phenoxide. prepared by strippmg a solution of phenol (4.7 g. 0.05 moles) and potassium hyma droxide (3.3 g. 0.05 moles 86.2% purity) in methanol Analysis Example No. X Y m.p.(b.p.)C %C %H %N 7(Cl %F 1 CN H 93-98 found 54.83 2.33 9.29 15.84

reqs. 54.56 2.29 9.09 18.49 2 Cl H 67-70 found 49.31 2.15 4.44 11.15 17.80 (5 11;311 190. reqs. 49.19 2.22 4.41 11.21 17.94 3 F H (9598/0.35 mm) found 51.77 2.50 4.77

C, -;H1F4NO;; reqs. 51.16 2.31 4.59 15.73 26.21 4 Br H 86-87 found 43.44 1.78 3.63 2213* 15.85 C H BrF NO reqs. 43.10 1.95 3.87 2207* 15.74 5 H H 47-48 found 55.42 3.00 4.73 19.85 c,.,11,.F.,No reqs. 55.12 2.85 4.95 20.13 6 C1 C1 8 found 44.24 1.42 4.04 20.15 15.98 C H Cl F NO reqs. 44.33 1.72 3.98 20.13 16.19

7rBr

EXAMPLE 1 ml.) is dissolved in sulfolane (75 g), and 3,4-

- dichloro-a,a,a-trifluorotoluene (10.8 g. 0.05 mole) Preparatlon of dded. The mixture 1s heated at 170C overnr ht then 1 -4- t h a g 2 Cyan? mflu?ro p to yl m Top enyl ether cooled, d1luted with benzene (250 ml.), and washed A $011190" 9 potasslun? hydroxlde mole with water (3 X 600 ml.). The organic phase is dried, 9 893% P y) and R- QP g- 005 mole) filtered through activated silica gel (20 g.) and the sollIl methanol 18 pp under reduced P vent removed. The residue (12.4 g.) is distilled to give sure. The residue is dissolved in sulfolane, 4-chloro-3- 2- hl -a,a,a t ifluom-p-tol l phenyl ether (9.9 g. cyano-a,a,a-trifluorotoluene (10.3 g. 0.05 mole) 72%) b.p. 85-90C/ 0.25 mm. contaminated with added, and the resulting solution heated at 150C for about 5% of 6-chlor -a,a,a-trifluoro m-tolyl phen- 5 hours. After cooling, the solution is diluted with benylether. zene (350 ml.) washed with water (6 X 250 ml.), dried, Found: C, 57.13; H. 3.09; Cl, 13.17; F, 20.86 Calcuand the solvent removed. The residue (12.5 g.) is related for: C l-l ClF o; C, 57.27; H.295; Cl, 13.00; F, crystallized from isopropanol to give 2-cyano-a,a,a- 20.91. v 'j trifluoro-p-tolyl-4-nitrophenyl ether (7.6 g., 49%) mp. b. 2-Chloro-a,a,a-trifluoro-p-tolyl-4-nitrophenyl ether 93-9 8C. A mixture offuming nitric acid (10 g. 0.16 mole) and concentrated sulfuric acid 10 g.) is added with vigor- EXAMPLE 2 ous stirring to 2-chloro-a,a,a-trifluoro-p-tolyl phen- Preparation of 50 ylether (27.3 g. 0.01 mole) initially at 75C, maintain- 2-chloro-a,a,a-trifluoro-p-tolyl-4-nitrophenyl ether Ia. 2-Chloro-a,a,a-trifluoro-p-cresol Chlorine gas is passed through a flow meter into a solution of a,a,a-trifluoro-p-cresol (4.05 g. 0.025 mole) in ethylene dichloride (200 m1.) at 0C. until the theoretical volume has been absorbed. The solvent is stripped off and the residue distilled to give 2-chloro-a,a.a-trifluoro-p-cresol (3.5 g. 71%) b.p. 80-82C at 33 mm. lb. Z-Chloro-a,oz.a-trifluoro-p-tolyl-4-nitrophenyl ether Potassium hydroxide 1.08 g. 0.0166 mole, 86% pure) is dissolved in methanol (10 ml.) and a solution of 2-chloro-a.0z.a-trifluoro-p-cresol (3.27 g. 0.0166 mole) in methanol added. The solvent is removed under pressure and sulfolane 100 ml.) added followed by p-fluoronitrobenzene (2.34 g.. 0.0166 mole) and the mixture heated at l30l50C for 7 hours. After cooling. the solution is poured into water (200 ml.) and exing a rate'of addition such that the temperature does not rise above 85C. After stirring at C for one-half hour, further mixed acid (5 g. 5 g.) is added and the mixture stirred for 15 minutes, cooled, diluted with water, and extracted with benzene (2 X 200 ml.). The extract is washed'with water and bicarbonate solution, dried, and the solvent removed. The residue (29.1 g.) is recrystallized from isopropanol to give 2-chloroa,a,wtrifluoro-p-tolyl-4nitrophenyl ether (12.7 g. 40%) mp. 67-70C. Analytical, and spectroscopic data confirm the identity of the products from Routes 1 and II. i i

EXAMPLE 3 Preparation-of 2, i a,a,a-Tetrafluoro-p-tolyl-4-nitrophenyl ether a) 2-Amino-a,a,d-trifluoro p tolylphenyl ether 2-Nitro-a,a,a-trifluoro-p-tolylphenyl ether (57.0 g., 0.209 mole) is dissolved in ethanol (200 ml.) and shaken in an atmosphere of hydrogen in a Parr apparatus in the presence of platinum oxide (100 mg.) until uptake is complete. The catalyst is removed by filtration and the solvent stripped off to give 2-amino-a,a,atrifluoro-p-tolyl phenylether (50.3 g. 99%) which is used without further purification.

Found: C, 61.76; H, 3.65; F, 22.35; N, 5.52. Calcu lated for: C H F NO; C, 61.66; H, 3.98; F, 22.51; N, 5.53.

b. 2,a.a,a-tetrafluoro-p-tolylphenyl ether 2-Amino-oz,a,a-trifluoro-p-tolylphenyl ether (25.3 g., 0.1 mole) is added to concentrated hydrochloric acid 100 ml.) and the mixture cooled to C. A solution of sodium nitrite (7.5 g. 0.1 mole) in water (5 ml.) is added dropwise with stirring, and after a total of 2 hours at l5C, the diazonium chloride solution is filtered and treated with a solution of sodium fluoroborate (25 g. 0.2+ mole) in water (30 ml.) and the dense fluborate salt filtered off and washed with ethanol and ether, then air dried, yield 23.0 g., decomposition point 190C. The salt is then added portionwise to a flask maintained in an oil bath at 200C, and when decomposition is complete, the residue is taken up in benzene (150 ml.), washed with water (4 X 100 ml.), dried, and

the solvent removed. The residue (10.3 g.) was extracted with isopropanol/hexane to give a residue which on distillation gives 2,a,a,a-tetrafluoro-ptolylphenyl ether (3.4 g. 14%), b.p. 90C/0.25 mm. c. 2,a,a,a-tetrafluoro-p-tolyl-4-nitrophenyl ether The above material is nitrated by the procedure described in Example 2 above for 2-chloro-a,a,atetrafluoro-p-tolyl-4-nitrophenyl ether.

EXAMPLE 6 Preparation of 2,6-Dichloro-a,a,a-trifluoro-p-tolyl4-nitrophenyl ether a. 3,4-Dichloro-a,a,a-trifluoro-5nitro toluene and 3,4- dichloro-a,a,a-trifluoro6-nitro toluene A mixture of 3,4-dichloro-a,a,a-trifluorotoluene (430 g., 2.0 moles), concentrated sulphuric acid (1200 ml.) and concentrated nitric acid (1200 ml., excess) was stirred at 90-100C for one-half hour. The mixture was then cooled and the acid phase discarded. The organic phase was washed with water, dilute sodium bicarbonate solution, potassium carbonate solution, dried, and distilled to give an approximately equal mixture (456 g., 89%) of 3,4-dichloro-a,a,a-trifluoro-5- nitrotoluene and 3 ,4dichloro-a,a,a-trif1uoro-6- nitrotoluene, b.p. 86C/3 mm. b. 2-Chloro-a,a,a-trifluoro-6-nitro-p-tolylphenyl ether A solution of potassium hydroxide (43.2 g. of 86% pure, 0.665 moles) in water ml.) was added slowly to a mixture of phenol (62.5 g., 0.665 mole) and the product from (a) above (450 g. total, equivalent to 0.665 mole of 3,4-dichloro-a,a,a-trifluoro-S-nitro toluene) in sulfolane (300 ml.) at 3068C. with stirring. After stirring at 4268C for a total of 1 hour the mixture was diluted with hexane (400 ml.) and water (600 ml.). The resulting layers were separated and the aqueous phase extracted once with hexane. The combined organic phases were washed with water and dilute caustic soda solution, dried and the solvent removed. The residue (471.3 g.) was distilled through a vacuum jacketed Vigreux column. No. 1 (272.2 g.) bp 100C/0.2

mm. consisted essentially of unreacted 3,4-dichloroa,a,atrifluoro-6-nitrotoluene. No. 2 (196.2 g.) b.p. 109-l19C/0.2 mm. was essentially pure desired diphenylether. A small residue (3.5 g.) was discarded. No. 2 crystallized and was recrystallized from 2- propanol (600 ml.) at 0C. to give 2-chloro-a,a.atrifluoro-6-nitro-np-tolylphenyl ether (144 g. 68%) m.p. 576lC. c. 2-Amino-6-chloro-a,a,a-trifluoro-p-tolyphenyl ether A solution of 2-chloro-a,a,a-trifluoro-6-nitro-ptolylphenyl ether 150 g., 0.472 mole) in ethanol 1200 ml.) was shaken in an atmosphere of hydrogen in a Parr apparatus in the presence of Pt0 (600 mg.) until uptake ceased. The catalyst was filtered off, the solvent removed, and the residue taken up in pentane (600 ml.) and filtered through activated silica gel 15 g.)

and the solvent removed. The residue was recrystallized from pentane at 20C. to give 2-amino-6-chloroa,a,a-trifluoro-p-tolylphenyl ether (94.1 g., 70%) m.p. 47-53C.

d. 2,6Dichloro-a,0:,a-trifluoro-p-tolylphenyl ether 2-Amino-6-chloro-01,0:,a-trifluoro-p-tolylphenyl ether (5.8 g., 0.02 moles) was ground with concentrated hydrochloric acid (70 ml.) to give a suspension of the amine hydrochloride. A solution of sodium nitrite (1.5 g., 0.022 moles) inwater (3 ml.) was added dropwise to the stirred suspension at 15C then the mixture was stirred for minutes at +3 -20C then filtered through a sintered glass filter. The filtrate was slowly added to a suspension of cuprous chloride (3.0

g.) in concentrated hydrochloric acid (20 ml.) at 3- 10C, then the temperature was slowly raised, finally to 90C for 20 minutes. The mixture was then cooled and neutralized with solid sodium bicarbonate and extracted with ether. The extract was washed with water and sodium carbonate solution, dried and stripped. The residue was distilled, to give the diphenylether (3.5 g.) as an oil which crystallized. The solid was taken upin pentane (10 ml.) and filtered through activated silica gel 5 g.) and the solvent removed. The residue .3.. 3 g.) was recrystallized from 2-propanol to give 2,6- dichloro-a,a,a-trifluoro-p-tolylphenyl ether (2.75 g. 45%) m.p. 48-50C. e. 2,6-Dichloro-a,a,a-trifluoro-p-tolyl-4-nitrophenyl ether 2,6-Dichloro-01,04,a-trifluoro-p-tolylphenyl ether (1.7

g., 0.0055 mole) was added to a cold (0C) mixture of concentrated sulphuric acid (1.7 g.) and concentrated EXAMPLES 7-13 Following the procedures of Examples 1 to 3, other diphenyl ethers of Formula I are prepared. Among the compounds which are prepared by these procedures are:

a,a,a,a',a'a'hexafluoro-2,4-xylyl-4-nitrophenyl ether, a",a ,a -2,4-xylyl-4-nitrophenyl ether,

1 l 2-chloro-6,a,a,0z-tetrafluoro-p-tolyl-4-nitrophenyl ether, a,a,a-trifluoro-2-iodo-p-tolyl-4-nitrophenyl ether, 2-cyano-6-chloro-a,a,a-trifluoro-p-tolyl-4- nitrophenyl ether, 2-brom0-0:,11,a,-4,6-xylyl-4-nitrophenyl ether, and 2-chloro-a,a,a,a',aa'-4,6-xylyl-4-nitrophenyl ether. These diphenyl ethers have herbicidal properties.

It should be noted that the diphenyl ethers of the invention can also be named correctly using different systerns of nomenclature. For example, the diphenyl ether of Example 1 can also be named as 2-cyano-4- trifluoromethyl-4nitrodiphenyl ether. v However, within the specification and claims of this invention the Chemical Abstracts system of nomenclature, as exemplified in Examples 1-13, has been followed.

The following examples show the herbicidal properties of the diphenyl ethers of the invention.

EXAMPLE 14 This example shows the herbicidal activity of diphenyl ethers of the invention towards a number of common weeds. Using the procedure described below, diphenyl ethers were evaluated for control of the following weeds: At pounds per acre:

Monocots barnyardgrass (Echinochloa crusgalli) crabgrass (Digitaria spp.)

nutsedge (Cyperus esculentus) wild oats (Avena fatua) Dicots bindweed (Convolvulus arvensis) curly dock (Rumex crispus) velvetleaf (Abutilon theophrasti) wild mustard (Brassica haber) At 2 and 4 pounds per acre:

Monocots barnyardgrass (Echinochloa crusgalli) crabgrass (Digitaria spp.)

downy brome (Bromus tectorum) foxtail (Setaria faberii) Johnsongrass (Sorghum halepense) nutsedge (Cyperus esculentus) quackgrass (Agropyron repens) ryegrass (Lolium perenne) wild oats (Avena fatua) yellow millet (Panicum miliaceaum) Dicots bindweed (Convolvulus arvensis) cocklebur (Xanthium pensylvanicum) curly dock (Rumex crispus) lambsquarters (Chenopodium album) morningglory (lpomoea purpurea) pigweed (Amaranthus retroflexus) smartweed (Polygonum pensylvaniacum) velvetleaf (Abutilon theophrasti) wild carrot (Daucus carota) wild mustard (Brassica haber) The following test procedure is employed. Seeds of selected crops and weeds are planted in soil in flats. For preemergence test, the flats are treated with the test compound immediately after the planting. For postemergence tests, the seeds are allowed to germinate, and after 2 weeks the flats are treated with the test compound; The compound to be evaluated is dissolved 65 in acetone, diluted with water, and sprayed over the flats using a carrier volume equivalent to 50 gallons per acre at the rate of application (pounds per acre, lb/A.) specified in the tables. About 2 weeks after the application of the test compound, the state of growth of the plants is observed and the phytotoxic effect of the compound is evaluated. Table ll gives the average percent control achieved by the test compounds in terms of the percent of the plants which are killed by the com- *M Monocots; D Dicots It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

We claim:

l. A compound of the formula wherein X is a halogen atom and wherein Y is a hydrogen or a halogen atom 2. A compound according to claim 1 wherein Y is a hydrogen atom.

3. A compound according to claim 2 wherein X is a halogen atom.

4. A compound according to claim 3 wherein X is a chlorine atom. I

5. A compound according to claim 1 wherein X is a halogen atom and Y is a halogen atom.

UNITED STATES PATENT AND TRADEMARK OFFICE Certificate Patent No. 3,888,932 Patented June 10, 1975 Horst O. Bayer, Colin Swithenbank & Roy Y. Yih

Application having been made by Horst O. Bayer, Colin Swithenbank & Roy Y. Yih, the inventors named in the patent above identified, and Rohm and Haas Co., Philadelphia, Pa., a Corp. of Delaware, the assignee, for the issuance of a certificate under the provisions of Title 35, Section 256, of the United States Code, deleting the name of Roy Y. Yih as a joint inventor, and a showing and proof of facts satisfying the requirements of the said section having been submitted, it is this 23rd day of Aug. 1983, certified that the name of the said Roy Y. Yih is hereby deleted from the said patent as a joint inventor with the said Horst O. Bayer & Colin Swithenbank.

Fred W. Sherling, Associate Solicitor 

1. A COMPOUND OF THE FORMULA
 2. A compound according to claim 1 wherein Y is a hydrogen atom.
 3. A compound according to claim 2 wherein X is a halogen atom.
 4. A compound according to claim 3 wherein X is a chlorine atom.
 5. A compound according to claim 1 wherein X is a halogen atom and Y is a halogen atom. 